1. Technical Field
The present invention relates to a MEMS device, a liquid ejecting head which is an example of the MEMS device, a liquid ejecting apparatus which is provided with the liquid ejecting head, a manufacturing method of a MEMS device, and a manufacturing method of a liquid ejecting head.
2. Related Art
An ink jet recording head, which is an example of the Micro Electro Mechanical Systems (MEMS) device, has a flow path forming substrate on which a pressure chamber that retains liquid is formed and a functional element (piezoelectric element) that is provided on one surface side of the flow path forming substrate, generates pressure variation in the liquid within the pressure chamber by driving the piezoelectric element, and ejects a liquid droplet from a nozzle that is linked to the pressure chamber.
As such a piezoelectric element, an element is suggested with a thin-film shape that is formed by film deposition and photolithography on the flow path forming substrate. It is possible to dispose the piezoelectric elements at high density by using the thin-film shape piezoelectric elements, on the other hand, electrical connection between the piezoelectric elements that are disposed at high density and a driving circuit is difficult.
For example, an ink jet recording head described in JP-A-2014-51008 has a pressure chamber forming substrate which forms a pressure chamber, a piezoelectric actuator (piezoelectric element) which applies ejection energy to ink within the pressure chamber, and a substrate on which a driver that drives the piezoelectric element is formed. The pressure chamber forming substrate is larger than a substrate on which the driver is formed, the piezoelectric element is blocked from the atmosphere by the pressure chamber forming substrate, the substrate on which the driver is formed, and an adhesive, and moisture-proofing of the piezoelectric element is achieved.
Furthermore, the piezoelectric element and the driving circuit are electrically connected via a bump. It is possible to easily electrically connect the piezoelectric element and the driving circuit even in a case where the piezoelectric elements are disposed at high density by using the bump that electrically connects the piezoelectric element and the driving circuit.
However, in a case where the pressure chamber forming substrate for achieving high density of nozzles that eject liquid is manufactured using a silicon single crystal substrate, and furthermore, the pressure chamber forming substrate for increasing ejectabilty and ejection precision of liquid is thinned, in the ink jet recording head described in JP-A-2014-51008, there is a problem in that mechanical damage tends to be generated on the pressure chamber forming substrate since the pressure chamber forming substrate is larger than the substrate on which the driver is formed and an end portion of the pressure chamber forming substrate overhangs from an end portion of the substrate on which the driver is formed.